Known as the Lada outside the Soviet Union, these Russian variants constituted the vast majority of 124 derived production, making it the fifth best selling automotive platform in history.

As a clean-sheet design[clarification needed] by Oscar Montabone, the chief engineer responsible for its development,[6] the 124 used only the all-synchromesh gear box from the Fiat 1500.

[6] The 124 featured a spacious interior, advanced coil spring rear suspension, disc brakes on all wheels and lightweight construction.

[8] The two Sport models were powered by an all-new 1.4-litre dual overhead camshaft engine producing 90 DIN-rated PS (66 kW; 89 hp) at 6,500 rpm.

[9] Following its introduction in 1966 with a publicity stunt, where a 124 was dropped by parachute from a plane,[10][11] the 124 won the 1967 European Car of the Year award.

[13] In addition to a 1.4-litre overhead valve engine, the 124 Special notably introduced all-new 5-link (four longitudinal, one transverse) solid axle rear suspension in place of the original 3-link design.

Besides engine and rear axle, notable mechanical changes from the regular 124 were an alternator replacing the dynamo, an uprated clutch, standard 155R13 Pirelli Cinturato radial tyres, and the addition of a vacuum servo to the all-disc braking system.

The interior featured a redesigned padded dashboard with an oval binnacle housing two round instruments and a car radio console, a steering wheel without horn ring, new door cards, and more supportive seats.

[15] At the November 1970 Turin Motor Show, Fiat introduced a round of updates for the entire saloon and estate 124 range, as well as a new model variant—the 124 Special T.[16] All models had gained air outlets added to the C-pillar for better ventilation, and a split brake circuit; while some features previously exclusive to the 124 Special such as servo-assisted brakes, back-up light and an alternator were made standard across the range.

[16] Berlina and Familiare both had a new grille with alternated chrome and black horizontal bars, and larger bumper over-riders.

A black, square-mesh radiator grille was crossed by a horizontal bright bar joining the dual headlamps; each of the four round lamps was set in its own square, bright-edged housing.

At the rear the lamps were also new—still horizontal and rectangular in shape unlike the ones used on the standard saloon—and the whole tail panel was surrounded by a chromed profile.

The "T" in 124 Special T stood for twin cam, hinting at the car's 1,438 cc dual overhead camshaft engine, derived from the Sport Coupé and Spider but in a milder state of tune.

Throughout the 1960s and 1970s, Fiat sought to extend its worldwide reach by licensing the 124 design following its discontinuation in mainstream Western European markets, including the widely known and most produced derivative, the Russian-built Lada, which sold over 15 million units.

In 1966, Fiat entered into a collaborative agreement with the Soviet government to establish car manufacture in the Samara region of Russia.